backend 409 on document conflict

backend/src/routes/documents.rs

@@ -303,7 +303,6 @@ struct UploadRequest {
 enum UploadOutcome {
     Created(DocumentDetailResponse),
     Reused(DocumentDetailResponse),
-    Skipped { document_id: Uuid },
 }
 
 #[derive(ToSchema)]
@@ -322,7 +321,7 @@ pub struct UploadDocumentForm {
     pub correspondents: Option<Vec<CorrespondentAssignmentInput>>,
     #[schema(nullable, example = "2024-01-01T00:00:00Z")]
     pub issued_at: Option<String>,
-    #[schema(nullable)]
+    #[schema(nullable, default = true)]
     pub skip_existing: Option<bool>,
 }
 
@@ -713,7 +712,7 @@ pub async fn get_document(
     responses(
         (status = 201, description = "Document created", body = DocumentDetailResponse),
         (status = 200, description = "Existing document reused", body = DocumentDetailResponse),
-        (status = 204, description = "Upload skipped because the document already exists")
+        (status = 409, description = "Document with identical contents already exists")
     ),
     tag = "Documents"
 )]
@@ -732,7 +731,7 @@ pub async fn upload_document(
     let mut tag_ids: Vec<Uuid> = Vec::new();
     let mut correspondents: Vec<CorrespondentAssignmentInput> = Vec::new();
     let mut issued_at_override: Option<NaiveDateTime> = None;
-    let mut skip_if_existing = false;
+    let mut skip_if_existing = true;
     let mut title_override: Option<String> = None;
 
     while let Some(field) = multipart.next_field().await.map_err(|err| {
@@ -913,10 +912,6 @@ pub async fn upload_document(
             );
             (StatusCode::OK, Json(detail)).into_response()
         }
-        UploadOutcome::Skipped { document_id } => {
-            info!(document_id = %document_id, "document upload skipped by client request");
-            StatusCode::NO_CONTENT.into_response()
-        }
     };
 
     Ok(response)
@@ -2138,11 +2133,15 @@ async fn process_upload(
                 info!(
                     document_id = %document.id,
                     checksum = %checksum_hex,
-                    "upload skipped existing document due to skip flag",
+                    "upload rejected because document already exists",
+                );
+                return Err(
+                    AppError::conflict("a document with the same contents already exists")
+                        .with_code("duplicate_document")
+                        .with_details(json!({
+                            "conflict_document_id": document.id,
+                        })),
                 );
-                return Ok(UploadOutcome::Skipped {
-                    document_id: document.id,
-                });
             }
 
             if let Some(issued_at) = issued_at_override {